Septic tank kit

ABSTRACT

The septic tank of the subject invention can be provided in kit form, and preferably comprises a tank lid, a tank bottom, a pair of opposing side walls, and a pair of opposing end walls having a tank flow outlet and a tank flow inlet, where a flange is affixed within the tank flow outlet and the tank flow inlet. The tank lid comprises a pair of lid openings, which are covered by hatch covers. The hatch covers comprise a hatch handle for ease of removal and are removably affixed to the tank lid with angle connection brackets. The septic tank is assembled using angle connection brackets, where the brackets are affixed to the tank lid, tank bottom, side walls, and end walls using, for example, stainless steel cap screws. A silicone sealant is interposed between the tank lid, tank bottom, side walls, end walls and the connection brackets, forming a substantially leak proof seal.

CROSS-REFERENCE TO A RELATED APPLICATION

This application is a continuation application of co-pending patentapplication Ser. No.10/675,365, filed Sep. 30, 2003; which is acontinuation of application Ser. No. 10/439,024, filed May 14, 2003, nowabandoned, which claimed the benefit of provisional patent applicationSer. No. 60/450,974, filed Feb. 28, 2003 and provisional patentapplication Ser. No. 60/415,458, filed Oct. 1, 2002; all of which arehereby incorporated by reference in their entirety.

FIELD OF THE INVENTION

The present invention relates generally to septic tanks, and moreparticularly, to a septic tank kit which can optionally be assembled atthe site of installation.

BACKGROUND OF THE INVENTION

Septic tanks are typically used at dwellings that are not connected topublic sewage facilities. The septic tank is typically locatedunderground and is basically a batch sewage processor. Sewage from thedwelling is sent to the septic tank where it is acted on bymicroorganisms, where through biochemical reactions the sewage isdecomposed. Subsequently, liquid and gaseous effluent is discharged intothe surrounding soil. Solids remaining in the tank are periodicallycleaned. More information regarding septic tanks can be found in, forexample, Woodson, R. Dodge: Builder's Guide to Wells and Septic Systems,McGraw Hill; and Burks, Bennette D. and Mary Margaret Minnis: OnsiteWastewater Treatment Systems, Hogarth House, Ltd. Both of these areincorporated herein by reference to the extent they are not inconsistentwith the following explicit teachings.

Prior art septic tanks are often made of concrete, glass fiberreinforced resin materials, or rotationally molded plastic materials.Because of the septic tank size and weight, they are typicallytransported to the work site by truck, and may require a crane forplacing into position.

BRIEF SUMMARY OF THE INVENTION

The septic tank of the subject invention is available as a septic tankkit which can be assembled on site comprising, in a preferredembodiment, a tank lid, a tank bottom, a pair of opposing side walls,and a pair of opposing end walls having a tank flow outlet and a tankflow inlet, where a flange is affixed at the tank flow outlet and at thetank flow inlet. The tank lid preferably comprises a pair of lidopenings, which are covered by removable hatch covers. The hatch coverspreferably comprise a hatch handle for ease of removal and in oneembodiment are removably affixed to the tank lid with angle connectionbrackets.

The septic tank is assembled using angle connection brackets, where thebrackets are affixed to the tank lid, tank bottom, side walls, and endwalls using fasteners such as, for example, stainless steel cap screws.A silicone sealant can be interposed between the tank lid, tank bottom,side walls, end walls, and the connection brackets, forming asubstantially leak proof sealing gasket.

The septic tank kit further preferably comprises a baffle positionedwithin the septic tank to form two compartments: an inlet compartmentideally but not necessarily encompassing approximately ⅔ of the totalvolume of the tank, and an outlet compartment. The baffle presents abarrier which enables the larger sediment to settle in the inletcompartment, with the remaining effluent flowing into the outletcompartment through a baffle port and/or over the top of the baffle ifthe baffle does not extend completely from the floor of the tank to thetank's ceiling.

To provide greater structural rigidity, the septic tank can comprisestructural support. In embodiments with a baffle, the baffle extendsupward from the bottom of the tank and from one side of the tank acrossto the other, thereby providing some additional internal horizontalsupport. If the baffle is an embodiment that extends upward completelyto the tank's ceiling, then it also provides additional internalvertical support. However in embodiments without a baffle, even when abaffle is present, additional internal support may be desired. Forexample, the inlet compartment can comprise vertical and horizontalstructural supports, where at least one vertical support member isinterposed between the tank lid and the tank bottom, being connected tothe tank bottom using, for example, a flange or collar. The inletcompartment can further comprise two or more horizontal support members,wherein at least one horizontal support is connected to and interposedbetween the side walls, and the at least one other horizontal support isconnected to and interposed between the inlet end wall and the baffle.The vertical support can be affixed to the horizontal supports toprovide greater stability.

The outlet compartment can optionally comprise at least one horizontalsupport, where the horizontal support is connected to and interposedbetween the outlet end wall and the baffle. Obviously, in view of theteachings herein, if vertical or other horizontal supports are desiredin the outlet compartment, they are easily provided as will be readilyapparent to the skilled artisan.

For ease of use and transportation to the work site, the septic tankstaught herein are available in an unassembled condition where they canthen be assembled on the work site. Although not necessary, it ispreferred that kits according to the subject invention includeinstructions for assembly into septic tanks.

This is the first teaching of using sheet plastic, or flat plasticpanels, for the construction of septic tanks. Acceptable plasticsinclude, but are not limited to, such plastics as homopolymerpolypropylene (homopolymer) or copolymer polypropylene (copolymer). Aswill be readily apparent to the skilled artisan in view of the teachingsherein, any and all plastics available as sheet stock (i.e., PVC,polyethylene) can be used to practice the subject invention. It is alsothe first teaching of the use of extrusion welding in the manufacture ofseptic tanks. Extrusion welding is a well-known technique where anextruded plastic wire, (for example, ⅛″ or 3/16″ diameter polypropylene)is superheated, melting and effectively forming a caulk between twoplastic sheets or panels. Superheated air from the tip of the weldinggun also heats and melts the panels and the bead of caulk forming ahomogeneous weld bonding the sheets (or whatever other forms of plasticare the subject of the weld) together. In addition, the subjectinvention constitutes the first use of plastic angles and specialplastic extrusions (such as, for example, right angle brackets of PVC,copolymer polypropylene or homopolymer polypropylene) with fasteners(such as, for example, stainless steel screws) to manufacture orassemble septic tanks.

All patents, patent applications and publications referred to or citedherein, or from which a claim for benefit of priority has been made, areincorporated by reference in their entirety to the extent they are notinconsistent with the explicit teachings of this specification,including U.S. Pat. No.4,882,046; U.S. Pat. No. 4,961,670; U.S. Pat.No.5,361,930; and U.S. Pat. No. 6,280,614.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of one embodiment of the subject inventionassembled septic tank kit.

FIGS. 2A-D are perspective views of the septic tank assembly of thesubject invention of FIG. 1 with the tank lid and hatches shown off.

FIG. 3 is a top view of a septic tank according to the subjectinvention.

FIG. 4 is a side view of a septic tank according to the subjectinvention.

FIG. 5 is an end view of a septic tank according to the subjectinvention.

FIGS. 6A-F are open top views of a septic tank according to the subjectinvention.

FIGS. 7A-E are open-end views of a septic tank according to the subjectinvention.

FIG. 8A-D are side views of the vertical section of a septic tankaccording to the subject invention.

FIG. 9 is a perspective exploded view of a septic tank kit according tothe subject invention.

FIG. 10 is a cross-sectional view of an embodiment of the double-channelangle connection bracket according to the subject invention.

FIG. 11 is the cross-sectional view of the double-channel angleconnection bracket depicted in FIG. 10, but with modified referencepoints for additional disclosure regarding specific dimensions of oneembodiment described herein.

FIG. 12 is a not-to-scale open top perspective view of an embodiment ofa septic tank according to the subject invention which has asubstantially trapezoidal cross-sectional appearance.

FIG. 13 is a not-to-scale open top perspective view of an embodiment ofa septic tank according to the subject invention which has asubstantially trapezoidal cross-sectional appearance.

FIG. 14 is a not-to-scale perspective view of an embodiment of a septictank according to the subject invention which has a substantiallytriangular cross-sectional appearance.

FIG. 15 is a not-to-scale open top perspective view of an embodiment ofa septic tank according to the subject invention which has asubstantially triangular cross-sectional appearance.

FIG. 16 depicts yet another alternative embodiment of a septic tankaccording to the subject invention which is substantially an invertedtriangular-based pyramid in appearance, depicted with an open top.

FIG. 17 depicts a side elevation of single unit modular riser accordingto the subject invention.

FIG. 18 depicts a top view of a single unit modular riser according tothe subject invention.

DETAILED DISCLOSURE OF THE INVENTION

As shown in FIGS. 1 and 9, one embodiment of a septic tank according tothe subject invention comprises a tank lid 2, a tank bottom 18, a pairof opposing side walls 8, and a pair of opposing end walls 20, 21, aninlet end wall 20 and an outlet end wall 21. The tank lid 2 preferablycomprises a pair of lid openings 16, which are covered by hatch covers1. The hatch covers 1 each comprise a hatch handle 3 for ease of removaland are removably affixed to the tank lid 2 with angle alignmentbrackets 19 using, for example, stainless steel cap screws 7. As shownin FIG. 8, the outlet 21 and inlet end walls 20 comprise tank flowoutlet 4 and a tank flow inlet 5 respectively, where a flange 6 isaffixed to each of the tank flow outlet 4 and tank flow inlet 5. Theflange 6 is used to connect each of the flow inlet 5 and flow outlet 4to the dwelling and drain field, respectively. In a preferredembodiment, flanges 6 can be plastic collars that are attached at tankflow outlet 4 and tank flow inlet 5 with a deformable O-ring seal placedbetween the collar and the surface of the end wall to provide a flexibleseal. In a particularly preferred embodiment, flanges 6 at tank flowoutlet 4 and tank flow inlet 5 are made of a flexible plastic or rubber,which is deformable while still maintaining an effective seal.Especially preferred in this regard are flanges such as the POLYLOK III,a septic tank seal available from Polylok, Inc., Yalesville, Conn.

In an embodiment, as shown in FIGS. 6-9, the septic tank is assembledusing angle connection brackets 11, which can be plastic or made of someother material rigid enough to permit the assembled tank to retain itsstructural integrity (such as, for example, stainless steel), whereinthe brackets 11 are affixed to the tank lid 2, tank bottom 18, sidewalls 8, and end walls 20, 21 using, for example, stainless steel capscrews 7. A silicone sealant 17 is interposed between the tank lid 2,tank bottom 18, side walls 8, end walls 20, 21 and the connectionbrackets 11, forming a substantially leak proof sealing gasket.Alternatively in this and other embodiments of the tank, other sealantssuch as PERMATEX or GE II silicone rubber sealant could be used as willbe readily apparent to the skilled artisan. Further, the angleconnection brackets can optionally be provided with sealant materialprior to packaging of the kit. In an embodiment, the sealant materialcan be of a different color from the panels which serve as tank walls,top, or bottom; and different from the color of the connection bracket;so that one can readily see that the sealant has been applied.Alternatively, or in addition to use of screws in assembly of this andother embodiments of the tank, extrusion welding can be used to connectand/or seal the various panels and other plastic parts to each other.

In an embodiment, the septic tank kit further comprises a baffle 10,wherein the baffle 10 is positioned within the septic tank forming twocompartments: an inlet compartment 22 encompassing approximately ⅔ ofthe total volume of the tank, and an outlet compartment 23. The baffle10 presents a barrier which enables the larger sediment to settle in theinlet compartment 22, with the remaining effluent flowing into theoutlet compartment 23 through the baffle port 12. Optionally, baffle 10does not comprise a baffle port, in which case the baffle 10 should notextend completely from the tank bottom all the way to the tank top sothat flow from the inlet compartment 22 into the outlet compartment 23is accomplished over the top of baffle 10.

In an embodiment, the septic tank kit further comprises a plurality ofstructural support members 13, wherein the structural support members 13are vertically and horizontally affixed to the tank bottom 18, sidewalls 8, and end walls 20, 21 optionally using a flange 6 at eachattachment point. If flanges 6 are used to affix structural supportmembers, then for this purpose it is generally preferred that they be ofa relatively rigid construction, sufficiently rigid to ensure that thestructural support members are affixed in place.

In an alternative embodiment, the structural supports 13 are connectedto the tank bottom 18, side walls 8, and end walls 20, 21 using angledconnectors 15.

In an embodiment, as shown in FIG. 9, the septic tank comprises two setsof structural support members 13. The inlet compartment 22 comprises atleast three structural supports 13, a vertical support member 24interposed between the tank lid 2 and the tank bottom 18, beingconnected to the tank bottom 18. The inlet compartment 22 furthercomprises two horizontal support members 25, 26, wherein a firsthorizontal support 25 is connected to and interposed between the sidewalls 8, and a second horizontal support 26 is connected to andinterposed between the inlet end wall 20 and the baffle 10. The outletcompartment 23 comprises at least one horizontal support 27, wherein thehorizontal support 27 is connected to and interposed between the outletend wall 21 and the baffle 10.

In an embodiment, the structural support members 13 are 3″ diameterschedule 80 PVC pipe. Three different exemplary embodiments for commontank applications are, for example, ½″ thick bottom, sides, and ends,with a ¾″ thick lid; ⅝″ thick bottom, sides, and ends, with a ¾″ thicklid; and ¾″ thick bottom, sides, ends, and lid. Angle brackets in anembodiment can be 2″×2″×0.2″ right angles, and the fasteners can be, forexample, stainless steel screws such as, for example, ¼″×14×1¼″ or¼″×14×1½″ hex head screws. As the ordinary artisan will readilyappreciate, the dimensions of the panels, angles, support members, andfasteners can be optimized for the particular task at hand, consideringthe strength of the materials involved. Preferably, for most standardseptic tank volumes, if the panels are made of copolymer polypropylene,they will be at least ¼″ thick and no more than 4″ thick, althoughdepending on the volume of tank desired, it may be optimal to havepanels with thicknesses outside of this range, as will be within theskill of the ordinary artisan to make such optimizations. As an exampleof the advantageous weight characteristics of septic tanks constructedin accord with the teachings herein, the following is a list ofapproximate weights of certain embodiments of tanks having variousvolumes, wherein the tanks are made with bottoms, sides, and ends of ½″thick copolymer and lids of ¾″ thick copolymer: Tank Volume in GallonsApproximate Weights (pounds) 300 ˜350 lbs. 750 ˜625 lbs. 900 ˜700 lbs.1050 ˜750 lbs. 1200 ˜810 lbs. 1500 ˜950 lbs.

The foregoing are merely intended to illustrate the advantageous weightbenefits of the subject tanks (as compared to the much heaver prior artconcrete tanks of the same volume). The weights can vary depending on anumber of factors such as panel thickness, panel dimension, variousassociated hardware (such as some types of fasteners), panelcomposition, etc., as would be readily apparent to the skilled artisan,and still would be within the scope of the subject invention.

In an embodiment, the septic tank lid 2, a tank bottom 18, a pair ofopposing side walls 8, pair of opposing end walls 20, 21, and hatchcovers 1 are made of plastic that is copolymer, or homopolymer.

In an embodiment, the septic tank lid 2 comprises only one opening.

In an embodiment, the tank flow inlet and tank flow outlet can bedisposed in the same panel, preferably separated by a baffle.

In alternative embodiments, any hatch covers can be made of the same, ordifferent, materials than the sides, ends, bottom, and lid.

Although septic tanks of the subject invention can be assembled and thentransported to the site of intended use for subsequent installation, ina method of use, the septic tank, which is available in kit form, isassembled at the work site. The septic tank is transported to the worksite and assembled as follows:

In an embodiment, the end walls 20, 21 and side walls 8 are connected tothe tank bottom 18 with the angle connection brackets 11, wherein thebrackets 11 are affixed using, for example, stainless steel cap screws7. Prior to assembly, a silicone sealant 17 is interposed between thetank bottom 18, side walls 8, and end walls 20, 21 and the connectionbrackets 11, forming a substantially leak proof seal to allow for properfunction of the septic tank.

In a preferred embodiment, connection brackets 11 are in the form ofdouble-channel angle brackets similar to that depicted in FIGS. 10 and11. Referring to FIG. 10, the double-channel angle bracket of thesubject invention comprises a deep panel receiving channel 101 and ashallow panel receiving channel 102 defined by external panel retainingwalls 107 and internal panel retaining walls 108. In the embodimentdepicted in FIG. 10, deep panel receiving channel 101 and shallow panelreceiving channel 102 are oriented perpendicular to each other, for easeof assembling substantially flat, sheet plastic panels into a septictank having two sides, two ends, a lid, and a bottom, for example suchas depicted in FIGS. 1-9. Flat panels are preferred for use according tothe teachings herein, for ease of packaging the kit and sealing thetank. However, as will be readily apparent to the skilled artisan,absolute flatness is not a requirement to practice the subjectinvention. Preferably, the panels of the bottom, sides, ends, and lidare substantially flat. A “substantially” flat panel is one whichdeviates from its plane by no more than d, where d²=(0.05)A, where A isthe area of the panel in square inches. The plane of the panel can bedefined by any 3 corners of the panel. In a preferred embodiment,d²=(0.045)A; it is more preferred that d²=(0.04)A; it is still morepreferred that d²=(0.035)A; even more preferred that d²=(0.03)A; yeteven more preferred that d²=(0.025)A; particularly preferred thatd²=(0.02)A; more particularly preferred that d²=(0.015)A; and mostpreferred that d²=(0.01)A.

In alternative embodiments of the septic tank of the subject invention,the angle between the deep panel receiving channel and the shallow panelreceiving channel can be either acute, or obtuse, as is required basedon the intended ultimate configuration of the tank. For example, for theassembly of a tank having triangular side panels assembled in pyramidalform, all angles would be acute. See, for example, FIG. 16.Alternatively, tanks having a substantially trapezoidal cross-sectionalappearance would comprise double-channel angle brackets which in somecases possessed an acute angle between the deep panel receiving channeland the shallow panel receiving channel, and in other places wouldrequire an obtuse angle between the panel receiving channels, as wouldbe readily apparent to one of ordinary skill in the art viewing theembodiments depicted in FIGS. 12 and 13. Other embodiments, such asthose having, for example, an octagonal cross-sectional appearance,would incorporate the use of double-channel angle brackets havingpredominantly obtuse angles between the receiving channels.

Returning to the embodiment depicted in FIG. 10, at the closed end ofeach receiving channel is preferably located a bottom stop 103 which isa slightly raised portion intended to prevent the edge of the insertedplastic panels from fully contacting the bottom of the panel receivingchannels. Side stops 104 extend into the panel receiving channels byprotruding from the inner surfaces of external panel retaining walls 107and from the inner surfaces of internal panel retaining walls 108. Eachside stop is defined in part by sloped panel accommodation surface 105and sealant retaining surface 106. Each sealant retaining surface 106 ispreferably substantially perpendicular to the internal surface of thepanel retaining walls 107 and 108 to more effectively retain compressedsealant within the interior of each panel receiving channel. Inoperation, side stops 104 serve to assist in centering the panels intheir respective panel receiving channels, and also to retain sealantmaterial compressed within the panel receiving channels. In a method ofuse, sealant is applied to the bottom of a panel receiving channel. Asthe panel is inserted into the panel receiving channel, its leadingedges may encounter the sloped panel accommodations surfaces 105 of sidestops 104. In a preferred embodiment, the sloped panel accommodationsurface is angled so as to allow the leading edge of the panel to slidedownward towards the bottom of the receiving channel. A panel isinserted fully into the channel, compressing the sealant until the panelcontacts bottom stop 103. Sealant is forced up each side of the panelreceiving channel and retained therein by sealant retaining surfaces 106of each side stop 104.

As will be readily apparent to the ordinary skilled artisan, the panelthickness can vary depending on the size of the tank desired and thestrength of the materials from which the panel is made, and thedimensions of the double-channel angle bracket according to the subjectinvention can be appropriately modified accordingly. However, forillustrative purposes, an example of a double-channel angle bracketdepicted in FIG. 11 has dimensions which are suitable for accommodatingpanels of ½ inch thickness, and are as follows:

AB and ST are ⅝ inch

CD, EF, IJ, RS, and TU are ¼ inch

GH is 2⅛ inches

KL and VW are 1⅛ inch

MN is 1¼ inch

PQ is ½ inch

QT and PS 1/16 inch and

X is effectively a 90° angle causing deep panel receiving channel 101and shallow panel receiving channel 102 to be perpendicular, with theinternal corner at X effectively rounded at ¼ inch radius.

In a embodiment, the double-channel angle connection brackets can beprovided with predrilled holes through which fasteners, such asstainless steel screws or any other fastener known to those of ordinaryskill in the art which is effective for assembling the tank, can beinserted. In an alternative embodiment, the double-channel angle bracketcan be drilled at the site of assembly. Optionally, as provided in thekit according to the subject invention, the double-channel connectionbrackets can be premounted on one or more of the edges of one or more ofthe panels in the septic tank kit.

In an embodiment, a baffle 10 is positioned within the partiallyassembled septic tank, forming two compartments, an inlet compartment 22and an outlet compartment 23, where the inlet compartment 22 encompassesapproximately ⅔ of the total volume of the tank. The baffle 10 presentsa barrier which enables the larger sediment to settle in the inletcompartment 22, with the remaining effluent flowing into the outletcompartment 23 through the baffle port 12.

In an embodiment, structural support members 13 are positioned withinand connected to the tank bottom 18, side walls 8, and end walls 20, 21.The inlet compartment 22 comprises at least three structural supports13, a vertical support 24 interposed between the tank lid 2 and the tankbottom 18, being connected to the tank bottom 18. The inlet compartment22 further comprises two horizontal supports 25, 26, where a firsthorizontal support 25 is connected to and interposed between the sidewalls 8, and a second horizontal support 26 is connected to andinterposed between the inlet end wall 20 and the baffle 10. The outletcompartment comprises at least one horizontal support 27, wherein thehorizontal support 27 is connected to and interposed between the outletend wall 21 and the baffle 10.

The tank lid 2 is positioned on top of the partially assembled septictank and connected to the brackets 11 using fasteners, such as, forexample, stainless steel screws.

In an embodiment, the tank lid 2 comprises pre-drilled connection holesto facilitate attachment to the brackets 11.

In an embodiment, either or both of the tank lid 2 and tank bottom 18can be provided in the kit with the connection brackets preattached toat least one edge thereof. In a preferred embodiment, double-channelangle connection brackets according to the subject invention areprovided in the kit preattached to the edges of either or both of thetank lid 2 and tank bottom 18, preferably with the connection bracketaffixed to the lid panel such that the edge of the lid panel is insertedinto deep panel receiving channel 101 of each double-channel connectionbracket affixed to its perimeter. Similarly, in an embodiment the bottompanel has double-channel connection brackets affixed thereto such thatthe panel edges are inserted into the deep panel receiving channel 101of each double-channel connection bracket around its periphery. In thisembodiment, as the kit is unpacked and the tank is assembled, the tankbottom 18 having double-channel angle connection brackets preaffixedaround its periphery will be configured such that side panels can beinserted into shallow panel receiving channels 102 and then ultimatelythe tank lid, also having double-channel angle connection bracketsaffixed around its periphery can be lowered into place, with the topedges of the panels making up the side and end walls being inserted intothe downward oriented shallow panel receiving channels 102 projectingperpendicularly downward from the periphery of the tank lid. Connectionbrackets are preferably used to connect the side walls to the end wallsalong the vertical edges where they meet. In a preferred embodiment,fasteners are inserted through the connection brackets and the panelscontained therein to fasten the walls, top, and bottom of the tank inplace. Extrusion welding can optionally replace or augment theconnection of panels one to another.

The hatch covers 1 are positioned and connected to the tank lid 2 usingalignment brackets 19 and appropriate fasteners, such as, for example,stainless steel screws.

In an embodiment, the tank lid 2 and the hatch covers 1 comprisepre-drilled connection holes to facilitate attachment to the alignmentbrackets 19.

Frequently, tanks according to the subject invention as well as othertanks of similar purposes, will be installed at a distance significantlybelow grade. In such cases risers are often needed to provide a linkfrom the lid opening in a tank up to the grade surface. Because thedistance that any particular tank is required to be buried below gradecan vary depending on location and purpose, it is necessary that risersof various heights be available for use in connection with tanksaccording to the subject invention. In that regard, advantageouslyprovided are modular risers, which can be made in a variety of heights,that are easily mounted to lid openings in tanks, and which can besealably stacked one on top of the other depending on the depth of eachtank with which they are used. An example of a single unit modular riseraccording to the subject invention is depicted in FIGS. 17 and 18. Suchrisers can advantageously be made of the same materials as the tanks ofthe subject invention. Preferably, the risers are made of a number ofpanels ¾ inch copolymer polypropylene, but the thickness of the materialcan vary depending on the anticipated loads it is to bear and dependingon the strength of materials used in its construction. FIGS. 17 and 18show a riser according to the subject invention having a horizontalbottom portion 751 and a horizontal top portion 752. Bottom portion 751and top portion 752 are preferably square or rectangular in shape, andhave internal edges 756 defining a centrally located opening 760 whichallows passage through each of 751 and 752. Bottom portion 751 can bemade as a single piece unit, or, in a preferred embodiment, is made byconnecting four planks at substantially right angles one to another,mitered at the corners for better fit, secured by screws 754 with themitered joints welded for additional strength. Top portion 752 can besimilarly constructed. Top portion 752 is provided with downwardlyextending sidewalls 753 which are also preferably ¾ inch copolymerpolypropylene, and define an internal space which connects the centrallylocated opening 760 of top portion of 752 with the centrally locatedopening of bottom portion 751. As will be apparent to the skilledartisan in view of the teachings herein, although a preferred embodimentcomprises four panels acting as sidewalls to define an internal space ofsubstantially square or rectangular cross-sectional appearance, thepanels could be configured to provide a trapezoidal cross-section; or 3panels could provide a triangular cross-section; or 5 panels couldprovide a pentagonal cross-section; a hexagonal cross-section wouldresult from 6 panels; etc. Even more panels could be used as is readilyapparent from the foregoing. The panels which serve as sidewalls 753 arepreferably mitered at the corners and welded where they meet for greaterstrength and water tightness. In addition to welding, screws such as,for example, #10 1½ inch stainless steel round washer head slot shankscrews 2-inch on centers can be used to hold the panels together. Topportion 752 and bottom portion 751 can then be attached to the top andbottom ends, respectively, of the side walls 753 to form a single unitmodular riser, such as that depicted in FIG. 17. In a preferredembodiment, all internal corners are welded, and top portion 752 andbottom portion 751 are additionally secured in place with stainlesssteel screws. Preferably, screws 757 used to attach bottom portion 751to side walls 753 are countersunk. Similarly, it is preferred thatscrews 758 used to attach top portion 752 to side panel 753 are alsocountersunk. This permits sealable stacking of individual unit modularrisers one on top of the other. To facilitate such stacking, it ispreferable that the centrally located openings in the top portions andbottom portions of the risers be of the same shape and dimensions, aswould be readily apparent to the skilled artisan. In operation, risersof various heights can be provided simply by manufacturing them out ofside panels of various heights. For example, assuming all panels to bemade of ¾ inch copolymer polyprolene, a 12-inch high riser would haveside walls 753 constructed of panels 10 ½ inches high. If a 48-inchriser was needed for a particular application, instead of a single unitriser 48 inches high, one could stack two 24-inch high risers such thatbottom portion 751 of one riser is attached to top portion 752 ofanother riser, preferably with #10 1½ inch stainless steel round washerhead slot shank screws 2-inch on centers, and optionally weldedtogether, or compressing a sealant material there between, or both.Bottom portion 751 of the bottom riser is attached to the lid opening ona tank which is to be installed below grade. The top portion 752 of theuppermost unit of the modular riser is then connectable to a hatch coverwhich would be at or about grade when installation of the tank iscomplete.

In alternative embodiments, the septic tank kit can, upon assembly,yield tanks of various dimensions and configurations, as will be readilyapparent to one of ordinary skill in the art in view of the teachingsherein. For example, an alternative embodiment is depicted in FIG. 12,wherein the assembled tank has a substantially trapezoidal cross-sectionappearance. FIG. 12 depicts the tank without its lid, and withoutoptional internal supports, being merely intended to illustrate thealternative configurations possible using substantially flat plasticpanels in the kit of the subject invention. In FIG. 12 are depictedopposing side walls 208, inlet end wall 220, outlet end wall 221, tankflow inlet 204, tank flow outlet 205, tank bottom 218, baffle 210, andbaffle port 212.

Referring to FIG. 13, an alternative embodiment, also of substantiallytrapezoidal cross-sectional appearance, is depicted open top. Thisembodiment represents an inversion of the embodiment depicted in FIG.12, but having improved anti-buoyancy characteristics due to theincreased surface area of the tank lid (not depicted) as compared to thetank bottom 318. In this embodiment are depicted inlet end wall 320,outlet end wall 321, tank flow inlet 304, tank flow outlet 305, opposingside walls 308, baffle 310, and baffle port 312.

Yet another alternative embodiment is depicted in FIG. 14, wherein theassembled tank has a substantially triangular cross-sectionalappearance. Represented in FIG. 14 are tank inlet end wall 420, tankflow inlet 404, side walls 408, lid openings 416, baffle 410, baffleport 412, tank outlet end wall 421, and tank flow outlet 405.

Turning now to FIG. 15, yet another tank according to the subjectinvention is depicted which has a substantially triangularcross-sectional appearance, and is shown open top. As compared to theembodiment depicted in FIG. 14, this embodiment has improvedanti-buoyancy characteristics due to the substantial surface area of thetank top (lid not depicted), and the almost negligible surface area ofthe bottom, which is formed at the vertex of the meeting of side walls508. Also represented in this figure are tank inlet end wall 520, tankflow inlet 504, tank outlet end wall 521, tank flow outlet 505, baffle510, and baffle port 512.

Still another embodiment of a tank assembly provided in kit formaccording to the subject invention is depicted in FIG. 16. Thisembodiment comprises a minimum of four substantially flat panels (if oneexcludes the optional baffle 610, which is depicted in thisconfiguration). Represented in FIG. 16 are three triangular shapedsidewalls 608, tank flow inlet 604, tank flow outlet 605, optionalbaffle 610, and baffle port 612. Not depicted is the triangular shapedpanel which would serve as a lid for this embodiment of the tank.Excluding the optional baffle, this embodiment of the tank comprisesfour substantially flat panels.

As is readily apparent to one of ordinary skill in the art in view ofthe foregoing, a wide variety of septic tank configurations can beprovided in kit form according to the teachings herein.

It should be understood that the examples and embodiments describedherein are for illustrative purposes only and that various modificationsor changes in light thereof will be suggested to persons skilled in theart and are to be included within the spirit and purview of thisapplication.

1. A septic tank comprising at least four substantially flat plasticpanels, means for sealably connecting the panels one to another, a tankflow inlet, and a tank flow outlet.
 2. A septic tank according to claim1, wherein said tank comprises a baffle, and wherein said baffle dividesthe interior of the tank into an inlet compartment and an outletcompartment.
 3. A septic tank according to claim 1, wherein said tankcomprises a plastic lid.
 4. A septic tank according to claim 3, whereinsaid lid comprises at least one lid opening.
 5. A septic tank accordingto claim 2, wherein said tank comprises a plastic lid.
 6. A septic tankaccording to claim 5, wherein said lid comprises at least one lidopening.
 7. A septic tank according to claim 6, wherein said lidcomprises at least one lid opening above said inlet compartment and atleast one lid opening above said outlet compartment.
 8. A septic tankaccording to claim 1, wherein the means for connecting comprises aplastic double-channel angle connection bracket; said double-channelangle connection bracket comprising: a deep panel receiving channel,defined by a first external panel retaining wall and a first internalpanel retaining wall; and a shallow panel receiving channel, angularlyconnected to said deep panel receiving channel, and defined by a secondexternal panel retaining wall and a second internal panel retainingwall.
 9. A septic tank according to claim 8, wherein said double-channelangle connection bracket further comprises a side stop extending fromsaid first external panel retaining wall into said deep panel receivingchannel; a side stop extending from said first internal panel retainingwall into said deep panel receiving channel; a side stop extending fromsaid second external panel retaining wall into said shallow panelreceiving channel; and a side stop extending from said second internalpanel retaining wall into said shallow panel receiving channel.
 10. Aseptic tank according to claim 9, wherein said double-channel angleconnection bracket further comprises a bottom stop disposed within eachof said deep panel receiving channel and said shallow panel receivingchannel.
 11. A septic tank according to claim 9, wherein each of saidside stops comprises a sloped panel accommodation surface.
 12. A septicaccording to claim 9, wherein said deep panel receiving channel and saidshallow panel receiving channel are perpendicular to each other.
 13. Aseptic tank according to claim 3, wherein said tank comprises at leastfive substantially flat plastic panels.
 14. A septic tank according toclaim 4, wherein said tank comprises at least five substantially flatplastic panels.
 15. A septic tank according to claim 5, wherein saidtank comprises at least five substantially flat plastic panels.
 16. Aseptic tank according to claim 6, wherein said tank comprises at leastfive substantially flat plastic panels.
 17. A septic tank according toclaim 7, wherein said tank comprises at least five substantially flatplastic panels.
 18. A septic tank according to claim 8, wherein saidtank comprises at least five substantially flat plastic panels.
 19. Aseptic tank according to claim 9, wherein said tank comprises at leastfive substantially flat plastic panels.
 20. A septic tank according toclaim 10, wherein said tank comprises at least five substantially flatplastic panels.
 21. A septic tank according to claim 11, wherein saidtank comprises at least five substantially flat plastic panels.
 22. Aseptic tank according to claim 12, wherein said tank comprises at leastfive substantially flat plastic panels.
 23. A septic tank according toclaim 3, wherein said tank comprises at least six substantially flatplastic panels.
 24. A septic tank according to claim 4, wherein saidtank comprises at least six substantially flat plastic panels.
 25. Aseptic tank according to claim 5, wherein said tank comprises at leastsix substantially flat plastic panels.
 26. A septic tank according toclaim 6, wherein said tank comprises at least six substantially flatplastic panels.
 27. A septic tank according to claim 7, wherein saidtank comprises at least six substantially flat plastic panels.
 28. Aseptic tank according to claim 8, wherein said tank comprises at leastsix substantially flat plastic panels.
 29. A septic tank according toclaim 9, wherein said tank comprises at least six substantially flatplastic panels.
 30. A septic tank according to claim 10, wherein saidtank comprises at least six substantially flat plastic panels.
 31. Aseptic tank according to claim 11, wherein said tank comprises at leastsix substantially flat plastic panels.
 32. A septic tank according toclaim 12, wherein said tank comprises at least six substantially flatplastic panels.
 33. A septic tank according to claim 23, wherein saidtank comprises a substantially flat plastic bottom panel; asubstantially flat plastic lid panel; two substantially flat plasticside panels; and two substantially flat plastic end panels, one of saidend panels having a tank flow inlet and the other of said end panelshaving a tank flow outlet.
 34. A septic tank according to claim 33,wherein said lid panel has at least one opening therein, and furthercomprising a hatch cover corresponding to each said opening in said lidpanel.
 35. A septic tank according to claim 33, further comprising abaffle, and wherein said baffle divides the interior of the tank into aninlet compartment and an outlet compartment.
 36. A septic tank accordingto claim 35, wherein said lid panel has at least one opening therein,and further comprising a hatch cover corresponding to each said openingin said lid panel.
 37. A septic tank according to claim 36, wherein saidlid panel comprises at least one lid opening above said inletcompartment and at least one lid opening above said outlet compartment.38. A septic tank according to claim 36, wherein the means forconnecting comprises a plastic double-channel angle connector bracket;said double-channel angle connection bracket comprising: a deep panelreceiving channel, defined by a first external panel retaining wall anda first internal panel retaining wall; and a shallow panel receivingchannel, angularly connected to said deep panel receiving channel, anddefined by a second external panel retaining wall and a second internalpanel retaining wall.
 39. A septic tank according to claim 37, whereinthe means for connecting comprises a plastic double-channel angleconnector bracket; said double-channel angle connection bracketcomprising: a deep panel receiving channel, defined by a first externalpanel retaining wall and a first internal panel retaining wall; and ashallow panel receiving channel, angularly connected to said deep panelreceiving channel, and defined by a second external panel retaining walland a second internal panel retaining wall.
 40. A septic tank accordingto claim 36, further comprising at least one plastic internal structuralsupport member selected from the group consisting of a verticalstructure support, a horizontal structural support extending betweenside panels, and a horizontal structural support extending between saidbaffle and an end panel.
 41. A septic tank according to claim 37,further comprising at least one plastic internal structural supportmember selected from the group consisting of a vertical structuresupport, a horizontal structural support extending between side panels,and a horizontal structural support extending between said baffle and anend panel.
 42. A septic tank according to claim 48, further comprisingat least one plastic internal structural support member selected fromthe group consisting of a vertical structure support, a horizontalstructural support extending between side panels, and a horizontalstructural support extending between said baffle and an end panel.
 43. Aseptic tank according to claim 39, further comprising at least oneplastic internal structural support member selected from the groupconsisting of vertical structure support, a horizontal structuralsupport extending between side panels, and a horizontal structuralsupport extending between said baffle and an end panel.
 44. A septictank according to claim 40, wherein said at least one plastic internalstructural support member comprises a polyvinylchloride pipe.
 45. Aseptic tank according to claim 41, wherein said at least one plasticinternal structural support member comprises a polyvinylchloride pipe.46. A septic tank according to claim 42, wherein said at least oneplastic internal structural support member comprises a polyvinylchloridepipe.
 47. A septic tank according to claim 43, wherein said at least oneplastic internal structural support member comprises a polyvinylchloridepipe.
 48. A septic tank kit comprising: at least four substantially flatplastic panels, one of said panels comprising a tank flow inlet and oneother of said panels comprising a tank flow outlet; and instructions forassembling said panels into a septic tank.
 49. A septic tank kitaccording to claim 48, further comprising means for connecting saidpanels to one another.
 50. A septic tank kit of claim 49, wherein saidmeans for connecting comprises a plurality of angle connection brackets.51. A septic tank kit of claim 40, wherein said angle connectionbrackets are double-channel angle connection brackets.
 52. A septic tankkit of claim 49, wherein said means for connecting comprises a pluralityof fasteners.
 53. A septic tank kit of claim 52, wherein said fastenerscomprise stainless steel screws.
 54. A septic tank kit of claim 48,wherein said kit comprises: a substantially flat plastic bottom panel; asubstantially flat plastic lid panel; two substantially flat plasticside panels; and two substantially flat plastic end panels, one of saidend panels having a tank flow inlet and the other of said end panelshaving a tank flow outlet.
 55. A septic tank kit of claim 54, whereinsaid kit further comprises a plurality of angle connection brackets. 56.A septic tank kit of claim 55, wherein said angle connection bracketsare double-channel angle connection brackets.
 57. A septic tank kit ofclaim 56, wherein said double-channel angle connection brackets areplastic.
 58. A septic tank kit of claim 54, wherein said lid panel hasat least one opening therein.
 59. A septic tank kit of claim 58, furthercomprising at least one hatch cover corresponding to each opening insaid lid panel.
 60. A method of providing a septic tank, comprising thesteps of: obtaining a septic tank kit which comprises at least foursubstantially flat panels, one of said panels comprising a tank flowinlet and one other of said panels comprising a tank flow outlet; thekit further comprising instructions for assembling the panels into aseptic tank; and assembling the contents of said kit into a septic tank.61. The method of claim 60, wherein the septic tank kit furthercomprises means for connecting the panels one to another.
 62. The methodof claim 61, wherein the means for connecting comprises a plurality ofangle connection brackets.
 63. The method of claim 62, wherein the angleconnection brackets are double-channel angle connection brackets. 64.The method of claim 61, wherein the means for connecting comprises aplurality of fasteners.
 65. The method of claim 64, wherein thefasteners comprise stainless steel screws.
 66. The method of claim 60,wherein the kit comprises: a substantially flat plastic bottom panel; asubstantially flat plastic lid panel; two substantially flat plasticside panels; and two substantially flat plastic end panels, one of saidend panels having a tank flow inlet and the other of said end panelshaving a tank flow outlet.
 67. The method of claim 66, wherein theseptic tank kit further comprises a plurality of angle connectionbrackets.
 68. The method of claim 67, wherein the angle connectionbrackets are double-channel angle connection brackets.
 69. The method ofclaim 68, wherein the double-channel angle connection brackets areplastic.
 70. The method of claim 66, wherein the lid panel has at leastone opening therein.
 71. The method of claim 70, wherein the kit furthercomprises at least one hatch cover corresponding to each opening in thelid panel.
 72. the method of claim 64, wherein the septic tank kitfurther comprises a plurality of angle connection brackets.
 73. Themethod of claim 72, wherein the angle connection brackets aredouble-channel angle connection brackets.
 74. The method of claim 73,wherein the double-channel angle connection brackets are plastic.